Re: [PATCH] libata: rewrite SCSI host scheme to be one per ATA host

James Bottomley
2009-04-22T19:27:25Z

On Wed, 2009-04-22 at 14:36 -0400, Jeff Garzik wrote:
> James Bottomley wrote:
> > On Wed, 2009-04-22 at 16:18 +0100, Alan Cox wrote:
> >>> Don't forget, there are ATAPI devices (some Sony CD burners and old
> >>> phase-changers come into mind) which *do* have multiple LUNs sitting
> >>> beyond the PATA port. I don't know if libata supports such setups (my
> >>> old OS/2 driver does) but one shouldn't hijack LUNs to emulate targets.
> >> It's a long time ago since I tested it but my 5 CD changer was correctly
> >> supported by libata (or more accurately by sr...).
> >
> > Well, sr supports the discovered CD/DVD; ch is the actual changer
> > manager. Usually ch attaches to one LUN and sr attaches to another.
>
> Like Alan's, if I understand him correctly, my PATA ATAPI CD changer
> simply presents a bunch of addressible LUNs. I never loaded, nor seemed
> to need, ch.

Yes, they both seem to be non standard changer implementations that just
present as many CDs as they could chage to.

The ch is actually a driver for devices which conform to the SCSI Media
Changer standard, which tends to present LUN zero as the smc device and
LUN1 as the selected CD/DVD

> I should boot a current libata and see how it behaves...

Might be fun.

James